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Polluted Fanga'uta Lagoon needs action by everyone, says CEO

Nuku'alofa, Tonga

Tonga's Parliament on the shores of the polluted Fanga'uta Lagoon. Nuku'alofa, 5 March 2020.

By Pesi Fonua

Tonga's national treasure the Fanga’uta Lagoon Catchment, home to 64 per cent of the population of Tongatapu, is seriously polluted and remains unhealthy because of long-term mismanagement, neglect and blatant disregard of laws that were designed to protect it.

In spite of the best efforts of Tongan experts over the last thirty years, to study the problems, propose solutions to restore ecosystems and engage the community in better outcomes, the health of the lagoon continues to decline. It has become Tongatapu's unhealthy heart.

Although a healthy lagoon is able to clean itself, Fanga‘uta Lagoon is receiving levels of pollutants that far exceed what it can assimilate.

Over the last five years two significant reports for the Tonga Government, supported by the United Nations Development Programme (UNDP/GEF), reiterated that “the health of the lagoon was found to be poor in all sections.” (Ridge to Reef Project1. 2.).

“The importance of this area and its value to people is not always considered on a day to day basis, by national planners or residents,” stated the 2016 report. “Many of the communities within the lagoon area are dependent for their livelihoods and wellbeing on the ecosystem services the lagoon provides.”

There has been “increasing community concern about contamination and loss of productivity of the lagoon.”

Dredging entrances

Paula Ma‘u, the CEO for MEIDECC (the Ministry including Environment) explained last week that they were currently looking at dredging the two shallow entrances.

“We are looking at action not just a report,” he said.

The narrowest entrance called Ava Tongo opens towards Nuku’alofa Harbour to the west, and a wider passage, called Manavanga, which opens towards the Piha Passage to the east.

Paula said that because entrances to Fanga’uta had not been dredged out for a long time, they are blocked up and that is why it takes 29 days for water to drain out to the open sea from the Fanga’uta Lagoon, and nine days from Fanga-kakau.

Paula said that the blockage of Fanga’uta Lagoon accelerated during the past few years. He said that the entrances to Fanga’uta used to be dredged every five years, enabling the water to flow. Since Environment came under the Ministry of Lands in 2014, the dredging of Fanga‘uta was overlooked.

Paula was convinced that once the Fanga’uta Lagoon and the two entrances, the Ava Tongo Passage and Manavanga Passage were dredged out it would help to clean up the lagoon.

Paula Ma'u, MEIDECC Office, 2 March 2020.

Moving the capital

Paula said that there had been a proposal by the Asian Development Bank (ADB) for Tonga to move the capital Nuku’alofa somewhere else because of sea-level rising.

Land in Tongatapu is sloping toward the lagoon, a geological tilting of the highly porous limestone aquifier toward the lagoon, which increases its vulnerability. The northern coast is lower and with the sea level rising about .66mm annually, the swamp areas of Tongatapu will gradually increase.

Paula, however, did not think that to move the Capital was an option.

He sincerely believed that dredging out Fanga’uta and allowing water to flow in and out from the open sea would enable fish and jelly fish to return to their breeding grounds.

Paula said that also in the pipeline was a plan to build foreshores and grow mangroves on the coast-line from Sopu to Hihifo to counter the sea level rising and the fact that the island is tilting.

In addition to growing mangroves and building foreshores, Paula stressed that the public must come to terms with the problems that we are facing and play their role and avoid polluting our land and the sea.

Fanga'uta Lagoon, Tongatapu.

Poor health

Fanga‘uta Lagoon, shaped like a pair of cupped hands (Fanga'uta and Fanga-kaukau), covering an area of between 28.35 to 38.1 square kms, encompasses an extremely important marine environment.

This is why Fanga'uta was declared as a marine reserve in 1974, when it was a healthy lagoon, with clear waters, patch reefs, thriving mangroves (a nursery for fish), at a time when communities enjoyed safe fishing in its sheltered waters and recreation on green shores.

Today, it's the water that is green. When you read the reports written by the experts it's not hard to understand why murky waters and algal growth are still dominant.

Management Plan unused

A Fanga'uta Lagoon Management Plan written in 2001 “has never been used” stated the latest Fanga'uta Stewardship Plan (2017), which was Gazetted under the Environment Act.

The Environmental Impact Assessments Act (2003) and Regulations (2010) require all development activities must undergo a level of environmental impact assessment, but this has not always happened.

The 2017 stewardship plan was another urgent call for action, because “unhealthy ecosystems and unsustainable livelihood practices are fragile, and will be vulnerable to the effects of climate change.”

Likewise, Tonga's five year 2015-2020 National Biodiversity Strategy and Action Plan (NBSAP), placed a strong emphasis on ecosystem-based management.

Both plans show that the status of the health of the lagoon has been in decline since the first survey in 1998 while the population has grown.

Poorly planned development

Today, the Fanga’uta Lagoon Catchment includes much of the capital, Nuku’alofa, and is home for 47,529 people from 8,279 households in 29 villages.

The areas of the lagoon closest to the mouth were found to be in better condition than the rest due to daily tidal water exchange.

However, in most parts the lagoon is a lot shallower than in the past, with depths between 1.4m and 6m and a total water volume of around 38,000 megalitres (1 Ml is equal to one million litres). It's filling up with lifeless sediment.

“The amount of mud, sand, rubble and rocks has increased and now covers 73% of the lagoon floor...mostly non-living sediments, showing that conditions in the lagoon are overall continuing to deteriorate,” stated the 2016 report.

The 2015 baseline studies found that “pollution in the lagoon is severe, coming from sewage, illegal rubbish disposal, agriculture and chemical use”. These land-based sources of pollution enter the lagoon through groundwater and surface runoff. The report describes a lagoon that has 'murky waters, with fish kills, and green algae growing on the sea grasses and coral in a process known as “eutrophication”. Extremely high levels of Arsenic, Copper and Chromium were found on a Tonga Forest Products site at Tokomololo and other areas, which find their way into the lagoon.

Between 2001 and 2014 there was very little monitoring on health of habitats or resource use in the area.

Many people have forgotten that the whole of Fanga'uta Lagoon was once declared a protected area under the National Birds Protection Act. Today the habitats are under extreme stress.

The area also has one of the highest concentrations of archaeological remains in the Pacific, and was important in the ancient world.

Land reclamation and poorly planned developments are continuing to destroy important ecosystems and heritage sites, despite specific recommendations in all the reports that certain areas be protected.

Docking facilities

The 2017 stewardship plan also warned that a full environmental impact assessment would be needed for “a large scale infrastructure development project currently being considered for the Fanga'uta Lagoon [that] involves dredging the entrance to the lagoon and developing docking facilities for boats within the lagoon.”

An abandoned causeway across Ava Tongo blocks a narrow entrance to Fanga'uta Lagoon.
  1. Status of Fanga'uta Lagoon 2016, Ridge to Reef Project, Kingdom of Tonga, UNDP/GEF.
  2. Status of Fanga'uta Lagoon 2015, Ridge to Reef Project, Kingdom of Tonga, UNDP/GEF.
  3. The Fanga'uta Stewardship Plan, A Healthy Lagoon Reflects a Healthy Land and People, Tonga Department of Environment, UNDP (GEF) 2017.